Peptide based cytotoxic T-cell vaccines; delivery of multiple epitopes, help, memory and problems

Synthetic CD8+ cytotoxic T-lymphocyte (CTL) peptide epitope based vaccines are being developed against a number of human diseases. Here we describe extensive preclinical testing of peptide epitope vaccines formulated with a protein as a source of CD4 help and Montanide ISA 720, an adjuvant currently in human clinical trials. Such water-in-oil formulations could effectively co-deliver several peptide epitopes and simultaneously induce multiple independent CTL responses. The efficiency of CTL induction by some peptides was, however, dependent on the aqueous buffer conditions, with poor performance correlating with non-covalent peptide oligomerisation. Any of a number of proteins currently used in human vaccines could supply CD4 help and no difference in CTL induction was obtained if the CD4 response was amnestic or a primary. Peptide immunisation was found to induce long term CTL memory and the recall of protective responses did not depend on an amnestic CD4 response. Slow pyroglutamic acid formation and rapid oxidation of methionine residues was observed in water-in-oil formulations, however, the latter had no effect on CTL induction. These data highlight the need to monitor for potential deleterious chemical events and interpeptide interactions, but illustrate that peptide based vaccination can effectively deliver multiple epitopes, in conjunction with any protein, and induce protective memory.

How reproducible is diurnal blood pressure rhythm in patients with secondary (renal) hypertension?

Abnormalities (reduction in/absence of) in diurnal bp rhythm are much more commonly seen in patients with chronic uremia than in patients with primary hypertension or in normal subjects. Target-organ damage is greater in these patients. However, the extent to which these diurnal bp rhythm changes are consistent or variable is untested. We retrospectively examined 223 ambulatory blood pressure monitoring (ABPM) traces in 92 patients with chronic uremia who had undergone ABPM at least twice (mean 2.3 ABPM traces/patient) over the period 1991-1997. ABPM technique and analysis were constant over this period. We found that for patients with chronic declining renal function but not yet on dialysis therapy, 67% retained the same diurnal rhythm from one ABPM recording to the next; if the known tendency for declining renal function to accompanied by a greater prevalence of "non-dipping" is taken into account, 82% of all patients had a "predictable" diurnal pattern. 79% of transplant patients, 87% of haemodialysis patients and 100% of CAPD patients retained the diurnal rhythmicity from one ABPM session to the next. Non-dipping was much more frequent than dipping (67% vs 33%). We conclude that abnormalities of diurnal BP rhythm are reasonably consistent in patients with renal hypertension, especially as renal function declines and patients enter the renal replacement therapy programme.

Fulminant meningococcal supraglottitis: An emerging infectious syndrome?

We report a case of fulminant supraglottitis with dramatic external cervical swelling due to associated cellulitis. Blood cultures were positive for Neisseria meningitidis. The patient recovered completely after emergency fiberoptic intubation and appropriate antibiotic therapy. We summarize five other cases of meningococcal supraglottitis, all reported since 1995, and discuss possible pathophysiologic mechanisms.

DNA adducts of 2,3-epoxy-4-hydroxynonanal: detection of 7-(1', 2'-dihydroxyheptyl)-3H-imidazo[2,1-i]purine and 1,N6-ethenoadenine by gas chromatography/negative ion chemical ionization/mass spectrometry

2,3-Epoxy-4-hydroxynonanal (EH) is a bifunctional aldehyde formed by epoxidation of trans-4-hydroxy-2-nonenal, a peroxidation product of omega-6 polyunsaturated fatty acids. EH is mutagenic and tumorigenic and capable of modifying DNA bases forming etheno adducts in vitro. Recent studies showed that etheno adducts are present in tissue DNA of humans and untreated rodents, suggesting a potential endogenous role of EH in their formation. A sensitive assay is needed so we can determine whether EH is involved in etheno adduct formation in vivo and study the biological significance of the etheno adducts in DNA. In this study, we developed a gas chromatography/negative ion chemical ionization/mass spectrometry assay for the analysis of 1, N6-ethenoadenine (epsilonAde) and 7-(1', 2'-dihydroxyheptyl)-3H-imidazo[2,1-i]purine (DHH-epsilonAde) in DNA; both are products from the reaction of adenine with EH. The assay entails the following sequence of steps: (1) addition of [15N5]epsilonAde and [15N5]DHH-epsilonAde to DNA as internal standards, (2) acid hydrolysis of DNA, (3) adduct enrichment by C18 solid phase extraction (SPE), (4) derivatization by pentafluorobenzylation (PFB), (5) separation of PFB-epsilonAde and PFB-DHH-epsilonAde on a Si SPE column, (6) acetonide (ACT) formation of PFB-DHH-epsilonAde, and (7) GC/MS analysis with selective ion monitoring (SIM). The limit of detection by on-column injection for PFB-epsilonAde monitoring of the (M - PFB)- ion at m/z 158 was 30 amol and for ACT-PFB-DHH-epsilonAde monitoring of the (M - PFB)- ion at m/z 328 was 0.4 fmol; the detection limits for the entire assay were 6.3 fmol for epsilonAde and 36 fmol for DHH-epsilonAde. In calf thymus DNA modified with EH at 37 degreesC for 50 h, both epsilonAde and DHH-epsilonAde were detected at high levels by this method, 4.5 +/- 0.7 and 90.8 +/- 8.7 adducts/10(3) adenine, respectively. These levels were also verified by HPLC fluorescence analysis, indicating that EH extensively reacts with adenine in DNA, forming etheno adducts. The high sensitivity of the assay suggests that it may be used in the analysis of ethenoadenine adducts in vivo.

Studies on experimental adjuvanted influenza vaccines: comparison of immune stimulating complexes (Iscoms) and oil-in-water vaccines

Detergent-disrupted influenza virus vaccines, formulated as Iscoms, or oil-in-water (o/w) emulsions, were administered parenterally to mice and evaluated for immunogenicity and protective efficacy. Both formulations enhanced both primary and secondary serum antibody responses. The magnitude of these responses with o/w emulsions was further enhanced by the addition of the non-ionic block copolymer L121 in the emulsion. Four weeks after primary immunization, mice were challenged by exposure to an aerosol containing infectious virus. Resistance to challenge in terms of survival rate and weight change correlated well with serum antibody titre for all formulations. Two major differences were observed between the adjuvant formulations. Iscom vaccines, formulated with Quil-A or the less toxic Quillaia saponin preparation Iscoprep 703, induced specific cytotoxic T-lymphocyte responses, whereas the o/w-based vaccines did not. In addition, dose-site reactivity studies in sheep showed that Iscom vaccines were less reactive than o/w-based vaccines, the degree of reactivity of the latter increasing sharply with increasing L121 concentration. On the basis of these studies, Iscoms were chosen for development as a potential adjuvant for human influenza vaccines.

A quantitative mannose 6-phosphate receptor-based in vitro assay for recombinant human N-acetylgalactosamine-4-sulfatase

An assay was developed, using two similar formats, to simultaneously measure both the lysosomal targeting receptor binding and enzyme activity of the recombinant human enzyme N-acetylgalactosamine-4-sulfatase. This assay also has potential application for all phosphorylated lysosomal enzymes that contain mannose-6-phosphate residues. The receptor was either purified from fetal bovine sera then adsorbed, or produced in situ by growing and fixing diploid human fibroblast-like cells, to a solid phase. The enzyme substrate was 4-methylumbelliferyl sulfate which fluoresces after cleavage of the sulfate moiety. Both the precursor and mature forms of the recombinant enzyme were used to demonstrate the specificity and usefulness of the assay. The assay is rapid and sensitive and has a wide dynamic range. Association between the receptor and the mannose-6-phosphate residues was abrogated in the presence of a competitive inhibitor, mannose 6-phosphate. However, partial activity was still measured when the mature enzyme was incubated in the presence of mannose 6-phosphate when using the fixed fibroblast format. This would indicate that the recombinant enzymes contain at least one terminal sugar moiety other than mannose 6-phosphate which can recognize receptors on the surface of human fibroblast-like cells. Other possible applications of this assay are also discussed.

Conjugated estrogen reduces transfusion and coagulation factor requirements in orthotopic liver transplantation

We conducted a prospective, randomized study to determine the efficacy of conjugated estrogen in reducing blood product transfusion during orthotopic liver transplantation (OLT). Patients undergoing OLT were included in the study. Only those having a reaction time of more than 30 mm or 15 min (19 -28 mm) on computed thromboelastography (CTEG) at the beginning of surgery were enrolled in the study. Patients were randomized to receive either conjugated estrogen (CE) or placebo. Every patient received a first dose of CE (100 mg i.v.) (20 mL) or placebo (20 mL of isotonic sodium chloride solution) at the beginning of the procedure and a second dose of CE (100 mg i.v.) or 20 mL of placebo (20 mL of isotonic sodium chloride solution) just after reperfusion of the new graft. The two groups were similar in age, weight, requirement for veno-veno bypass, time on veno-veno bypass, CTEG measurement, and preoperative hemoglobin and platelet values. Blood products were given in relation to hematocrit and coagulation (CTEG) variables, which were measured every hour during the surgery. The amount of transfused blood products did not differ in terms of units of cryoprecipitate, but the intraoperative requirements for red blood cells (6 +/- 3 vs 9 +/- 6 U; P = 0.05), platelets (12 +/- 8 U vs 18 +/- 10 U; P = 0.05) and fresh-frozen plasma (3 +/- 3 U vs 6 +/- 4 U; P = 0.001) was significantly less in the estrogen group than in the control group. We conclude that CE is associated with a significant decrease in use of fresh-frozen plasma, platelets, and red blood cells during OLT.

IMPLICATIONS

In this study, we prospectively investigated whether i.v. conjugated estrogen could decrease blood product transfusion during orthotopic liver transplantation. Conjugated estrogen-treated patients received less fresh-frozen plasma, red blood cells, and platelets. In this population of patients, conjugated estrogen can be a useful addition in coagulation management during orthotopic liver transplantation.

Conjugated estrogen reduces transfusion and coagulation factor requirements in orthotopic liver transplantation

We conducted a prospective, randomized study to determine the efficacy of conjugated estrogen in reducing blood product transfusion during orthotopic liver transplantation (OLT). Patients undergoing OLT were included in the study. Only those having a reaction time of more than 30 mm or 15 min (19 -28 mm) on computed thromboelastography (CTEG) at the beginning of surgery were enrolled in the study. Patients were randomized to receive either conjugated estrogen (CE) or placebo. Every patient received a first dose of CE (100 mg i.v.) (20 mL) or placebo (20 mL of isotonic sodium chloride solution) at the beginning of the procedure and a second dose of CE (100 mg i.v.) or 20 mL of placebo (20 mL of isotonic sodium chloride solution) just after reperfusion of the new graft. The two groups were similar in age, weight, requirement for veno-veno bypass, time on veno-veno bypass, CTEG measurement, and preoperative hemoglobin and platelet values. Blood products were given in relation to hematocrit and coagulation (CTEG) variables, which were measured every hour during the surgery. The amount of transfused blood products did not differ in terms of units of cryoprecipitate, but the intraoperative requirements for red blood cells (6 +/- 3 vs 9 +/- 6 U; P = 0.05), platelets (12 +/- 8 U vs 18 +/- 10 U; P = 0.05) and fresh-frozen plasma (3 +/- 3 U vs 6 +/- 4 U; P = 0.001) was significantly less in the estrogen group than in the control group. We conclude that CE is associated with a significant decrease in use of fresh-frozen plasma, platelets, and red blood cells during OLT.

IMPLICATIONS

In this study, we prospectively investigated whether i.v. conjugated estrogen could decrease blood product transfusion during orthotopic liver transplantation. Conjugated estrogen-treated patients received less fresh-frozen plasma, red blood cells, and platelets. In this population of patients, conjugated estrogen can be a useful addition in coagulation management during orthotopic liver transplantation.

Comparison of neutrophil and monocyte function by microbicidal cell-kill assay in patients with cancer receiving granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, or no cytokine after cytotoxic chemotherapy: a phase II trial

Functional effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) and recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) were prospectively measured by harvesting blood samples from 51 oncology patients (21 who were receiving no cytokines, 14 receiving rhGM-CSF, and 16 who were receiving rhG-CSF) just before cytotoxic chemotherapy (baseline) immediately before the last cytokine dose (pre), 2 hours after the last cytokine dose (post), and 48 hours after the pre period (follow-up). Neutrophils and monocytes were separated and functional effects were measured by comparing cell-kill percentages, as determined by a microbial cell-kill assay against Staphylococcus aureus and Candida albicans. Optimal cell concentrations (2 x 10(6) monocytes/ml; 4 x 10(6) neutrophils/ml) and effector-to-cell ratios (1:50) were initially determined with blood samples harvested from 23 healthy volunteers. Results in oncology patients indicated that rhGM-CSF improved monocyte-killing activity against S. aureus at follow-up, compared with controls (p = 0.0094) and compared with monocytes from rhG-CSF-treated patients at the post period (p = 0.014). Cell-killing percentage of the rhGM-CSF-treated patients was also enhanced against C. albicans during the post period, compared with controls (p = 0.011) and rhG-CSF-treated patients (p = 0.067). Neutrophil activity was not altered by either cytokine. In conclusion, monocyte-induced microbial killing was enhanced in oncology patients receiving rhGM-CSF after cytotoxic chemotherapy, compared with patients receiving rhG-CSF or no cytokines. No differences in neutrophil activity were observed between patients receiving either cytokine.

Phosphorylation of calmodulin alters its potency as an activator of target enzymes

Previous work has shown that calmodulin (CaM) is constitutively phosphorylated in rat liver, probably by casein kinase II [Quadroni, M., James, P., and Carafoli, E. (1994) J. Biol. Chem. 269, 16116-16122]. A procedure is now described for the isolation of the phosphorylated forms of calmodulin (PCaM) free from CaM, since in vitro phosphorylation experiments yield a 50:50 mixture of 3-4 times phosphorylated CaM and native CaM. The activation of six target enzymes by PCaM was tested: myosin light chain kinase, 3',5'-cyclic nucleotide phosphodiesterase, plasma membrane Ca2+-ATPase, Ca2+-CaM-dependent protein phosphatase 2B (calcineurin), neuronal nitric oxide synthase, and CaM-kinase II. In general, the phosphorylation of CaM caused a decrease in enzyme binding affinity, increasing the Kact by 2-4-fold for MLCK, PDE, PM Ca2+-ATPase, and calcineurin. The Vmax at saturating concentrations of PCaM was less affected, with the exception of CaM-kinase II, which was only minimally activated by PCaM and NOS whose Vmax was increased 2.6 times by PCaM with respect to CaM. Phosphorylation of calmodulin had very little effect on the binding of calcium to the enzyme despite the fact that Ser 101 which is phosphorylated is located in the third calcium binding loop. CD measurements performed on CaM and PCaM indicated that phosphorylation causes a marked decrease in the alpha-helical content of the protein. Phosphorylated CaM is very prone to dephosphorylation and was thus tested as a substrate for several phosphatases. It was unaffected by calcineurin (PP2B), but was a reasonable substrate for the pleiotropic phosphatases PP1gamma and PP2A.

Assessment of the effects of combination therapy with ciprofloxacin and fenbufen on the central nervous systems of healthy volunteers by quantitative electroencephalography

The potential effects of concurrent administration of fenbufen and ciprofloxacin on central nervous system activity in healthy young subjects were investigated by electroencephalography (EEG). Visual analog scales (VAS) were used to assess subjective measures of concentration, vigilance, tension, and irritability. When ciprofloxacin was administered in combination with fenbufen, none of the EEG parameters or VAS ratings measured were significantly different from those measured when the drugs were administered alone.

A two-dose hepatitis B vaccine regimen: proof of priming and memory responses in young adults

This study shows that two doses of a recombinant hepatitis B vaccine (10 micrograms or 20 micrograms of HBsAg per dose), administered 6 months apart to young, healthy adults, can induce an antibody (anti-HBs) response similar to that expected with the standard three-dose regimen of this vaccine given at intervals of 0, 1, and 6 months. While only 46-67% of the vaccinees displayed a protective anti-HBs titer of > or = 10 mIU ml-1 prior to the receipt of the second dose at 6 months, virtually all were primed as 97-99% of the subjects developed such a titer when tested a month after the second dose. Among vaccinees given 10 or 20 microgram doses, respectively, the secondary rise in antibody following the second dose yielded geometric mean titers (GMTs) of 1103 and 2538 mIU ml-1, respectively. The study further demonstrated that a two-dose regimen of vaccination induced strong immunologic memory for HBsAg, as a booster dose of vaccine given 2 years later resulted in a rapid and vigorous anamnestic antibody response.

Effectiveness of conjugated estrogen in orthotopic liver transplantation

BACKGROUND

A retrospective study was conducted at a university hospital to determine the efficacy of conjugated estrogen in reducing blood product transfusion during orthotopic liver transplantation.

METHODS

The charts of patients who had orthotopic liver transplantation were retrospectively reviewed. Only those having a reaction time > 30 mm or 15 minutes (normal = 19 mm to 28 mm) on computerized thromboelastogram (CTEG) at the beginning of surgery were included. One group of patients received a first dose of conjugated estrogen (100 mg i.v.) at the beginning of the case and a second dose (100 mg i.v.) just after reperfusion of the new graft. The control group did not receive estrogen. The two groups were similar in age, weight, first TEG measurements, final intraoperative hemoglobin concentration and platelet count. Blood products were given in response to hematocrit and CTEG measurements, which were determined every hour during surgery.

RESULTS

The two groups did not differ in units of cryoprecipitate and platelets administered, but the intraoperative requirements for red blood cells and fresh frozen plasma were significantly lower in the estrogen group than in the control group.

CONCLUSIONS

Administration of conjugated estrogen is associated with a statistically significant decrease in use of red blood cells and fresh frozen plasma during orthotopic liver transplantation.

Progression of diabetic nephropathy--is diurnal blood pressure rhythm as important as absolute blood pressure level?

BACKGROUND

Hypertensive non-diabetic patients who lack the normal nocturnal decline in blood pressure ('non-dippers') have an increased incidence of cardiovascular complications. Poor blood pressure control is known to exacerbate the decline in glomerular filtration rate in patients with diabetic nephropathy.

METHODS

The aim of this study was to assess the contribution of abnormal blood pressure diurnal rhythm to the progression of diabetic nephropathy. We retrospectively studied 26 diabetic patients with hypertension, proteinuria and relentless progressive impairment of renal function due to diabetic nephropathy between 1990 and 1996. Patients underwent ambulatory blood pressure monitoring and were classified as either 'dippers' or 'non-dippers' according to their blood pressure diurnal rhythm. Dippers were patients whose mean sleeping blood pressure (both systolic and diastolic) was 10% less than blood pressure whilst awake. Weight, glycated haemoglobin, serum creatinine (micromol/l) and blood pressure (mmHg) were recorded on a 3-monthly basis. Twenty four hour urine protein excretion and creatinine clearance were recorded annually. The rate of decline of creatinine clearance was derived from serum creatinine estimation.

RESULTS

In the 'dipper' group, the rate of decline of creatinine clearance was -2.9 ml/min/year and in those with abnormal blood pressure diurnal rhythm it was -7.9 ml/min/year (P<0.05). There was no significant difference in day-time mean blood pressures, glycated haemoglobin, age and numbers with insulin-dependent diabetes mellitus.

CONCLUSION

We found that there was a profound effect of non-dipping upon the rate of decline of renal function in patients with diabetic nephropathy.

Predicting high-risk years for malaria in Colombia using parameters of El Niño Southern Oscillation

The interannual variation in malaria cases in Colombia between 1960 and 1992 shows a close association with a periodic climatic phenomenon known as El Niño Southern Oscillation (ENSO). Compared with other years, malaria cases increased by 17.3% during a Niño year and by 35.1% in the post-Niño year. The annual total number of malaria cases is also strongly correlated (r = 0.62, P < 0.001) with sea surface temperature (SST) anomalies in the eastern equatorial Pacific, a principal parameter of ENSO. The strong relation between malaria and ENSO in Colombia can be used to predict high and low-risk years for malaria with sufficient time to mobilize resources to reduce the impact of epidemics. In view of the current El Niño conditions, we anticipate an increase in malaria cases in Colombia in 1998. Further studies to elucidate the mechanisms which underlie the association are required. As Colombia has a wide range of climatic conditions, regional studies relating climate and vector ecology to malaria incidence may further improve an ENSO-based early warning system. Predicting malaria risk associated with ENSO and related climate variables may also serve as a short-term analogue for predicting longer-term effects posed by global climate change.

An investigation of the effect of advancing uraemia, renal replacement therapy and renal transplantation on blood pressure diurnal variability

BACKGROUND

Ambulatory blood pressure recordings have been shown to correlate better with target organ damage than have isolated clinic blood pressure readings. There have been some small studies demonstrating that abnormal blood pressure diurnal rhythm is common in uraemia and in patients on renal replacement therapy. Abnormal blood pressure diurnal rhythm itself may be a risk factor for accelerated target organ damage.

METHODS

We retrospectively studied 480 ambulatory blood pressure recordings in 380 patients with essential hypertension, secondary hypertension, and on renal replacement therapy. We examined diurnal blood pressure rhythm in each group.

RESULTS

Abnormal blood pressure diurnal rhythm (non-dipping) is significantly more prevalent in patients with underlying renal disease, even with normal excretory renal function (53%) than in age-, sex-, and race-matched controls with essential hypertension ((30%), P < 0.01). In patients with renal disease the prevalence of non-dipping rose with worsening renal function, reaching statistical significance once plasma creatinine was greater than 400 mumol/l. There was a direct correlation between plasma creatinine and percent decline in blood pressure at night for both systolic (r = 0.23) and diastolic (r = 0.24) blood pressure in patients with underlying renal disease and impaired excretory renal function. High prevalences of abnormal diurnal BP rhythm are seen in patients on haemodialysis (82%), peritoneal dialysis (78%), patients with plasma creatinine > 600 mumol/l (75%), and in renal transplant recipients (74%).

CONCLUSIONS

Abnormal blood pressure diurnal rhythm ('non-dipping') is significantly more common in secondary than in primary hypertension, even with normal renal function. Abnormal blood pressure diurnal rhythm becomes increasingly common with advancing uraemia. Once the plasma creatinine is greater than 600 mumol/l the prevalence of non-dipping is the same as that seen with renal replacement therapy. This phenomenon is not modulated by successful renal transplantation.